From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DECABC43334 for ; Mon, 4 Jul 2022 14:40:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233895AbiGDOj5 (ORCPT ); Mon, 4 Jul 2022 10:39:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234716AbiGDOjW (ORCPT ); Mon, 4 Jul 2022 10:39:22 -0400 Received: from mail-pg1-x533.google.com (mail-pg1-x533.google.com [IPv6:2607:f8b0:4864:20::533]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DCC68DF1D for ; Mon, 4 Jul 2022 07:39:12 -0700 (PDT) Received: by mail-pg1-x533.google.com with SMTP id s206so9112984pgs.3 for ; Mon, 04 Jul 2022 07:39:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=E3vZsiiHeLdWlriZeHfJHXGRio5cCE6j1rfnsSoRqsw=; b=kHaopAihyE/nO3+lgLXeoOf+vHGg+EnpfYQEIqMtVAgok67vFg7RkZFX5AurqesDmd Va/7byZR7sPYp8k6miFOW3N8wSbxVWAD3s09CECDgXjF649bgie+9Sf4pWomXlHzDPcg hxIN2mpdlwFfinWQyv1NIAO7brvnHW10AqdDnSoS9Gq9yrvcRUE7FrD0UA1EEJagcM3Y 1jLvs0fitrTHXYeq82/awdHX836trFf9XaN48SqpFYeU7w6hHcyT0T1U40k5Duu/UXl9 FO0BwuuYYLuloQsbSUncZCz4+Rn6jJgosrBvooEn136CBYKAtd5Ggeh9Ghg2IBv0tzeo M82w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=E3vZsiiHeLdWlriZeHfJHXGRio5cCE6j1rfnsSoRqsw=; b=jypzjSecoLbGuIs9oD+ePJ6R2jLDiAKKFe7QAAeSJw82pdmmWCm9gYPbd9KvVYpyLb 17uTCwhYnOaUrT284b3elc3tA1umx0VN32tqbrv+H4Firn6Chu2zrANq4wcHSfJLCJNE OVhRKqd0+QA0lGJjM47zkN35NPMpuO6NOWVH2At/EBylPWBHSc1ZLD9bei20tSV8M2jU 8dLb4sZ8m37Wknolc74/WtfzCSXlFzSQQZ2U//XS3T5IO8kga/4B4SG//wni1iLx9MZm U30vJKU49YmtUmJkPMu01uz+Gsu9QGkOY5aKwM81Ucw42MQ9wxwDZUSK44Ll3fmYQbVw KBVw== X-Gm-Message-State: AJIora+WbVfiLWUUkMS5vFINsWH/nTA1bmSsQ9LUhkphX3DSD0gQMx6E cArKa/fEfE2HmZsOgyis3sOrN+OLs/4= X-Google-Smtp-Source: AGRyM1tGv39z6d1FCO96hMCb97W+vTPVOrGKw/EqQYXSN6tTY/EMQsWHdDI6HjPBMUBU5xJzZAr/FA== X-Received: by 2002:a63:2c89:0:b0:411:66bf:9efc with SMTP id s131-20020a632c89000000b0041166bf9efcmr25069380pgs.589.1656945552669; Mon, 04 Jul 2022 07:39:12 -0700 (PDT) Received: from bobo.ozlabs.ibm.com ([203.221.247.188]) by smtp.gmail.com with ESMTPSA id u13-20020a63454d000000b0040d2224ae04sm20534365pgk.76.2022.07.04.07.39.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Jul 2022 07:39:12 -0700 (PDT) From: Nicholas Piggin To: Peter Zijlstra Cc: Nicholas Piggin , Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng , linux-kernel@vger.kernel.org Subject: [PATCH 12/13] locking/qspinlock: separate pv_wait_node from the non-paravirt path Date: Tue, 5 Jul 2022 00:38:19 +1000 Message-Id: <20220704143820.3071004-13-npiggin@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220704143820.3071004-1-npiggin@gmail.com> References: <20220704143820.3071004-1-npiggin@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org pv_wait_node waits until node->locked is non-zero, no need for the pv case to wait again by also executing the !pv code path. Signed-off-by: Nicholas Piggin --- kernel/locking/qspinlock.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 9db168753124..19e2f286be0a 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -862,10 +862,11 @@ static inline void queued_spin_lock_mcs_queue(struct qspinlock *lock, bool parav /* Link @node into the waitqueue. */ WRITE_ONCE(prev->next, node); + /* Wait for mcs node lock to be released */ if (paravirt) pv_wait_node(node, prev); - /* Wait for mcs node lock to be released */ - smp_cond_load_acquire(&node->locked, VAL); + else + smp_cond_load_acquire(&node->locked, VAL); /* * While waiting for the MCS lock, the next pointer may have -- 2.35.1